Mac Book and External Hard Drive Capabilities

I've been trying to upload some AVI formatted videos from my macbook to my Seagate external hard drive and it won't let me. I've uploaded AVI videos from my PC to this same hard drive and it accepts them with no problem.

In addition I can take AVI formatted videos from the hard drive and drag them onto my macbook's hard drive without a problem.

I'm unfamiliar with the different hard drive formats but any suggestions as to how I can circumvent this annoying problem would be greatly appreciated.


Thanks!

The terminology is "copy" not upload (from the Mac to the hard drive and vice versa). The hard drive is most likely formatted to NTFS which means your Mac can read from it but not write to it. You either have to install a driver on your Mac to enable write capability or reformat the external hard drive to a file format compatible with your Mac.